A theoretical study of the mass–temperature relation for clusters of galaxies     

A. Del Popolo † 《Monthly notices of the Royal Astronomical Society》2002,336(1):81-90

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Challenging a Paradigm: Do We Need Active and Inactive Areas to Account for Near-Nuclear Jet Activity?     

Crifo  J.-F.  Rodionov  A. V.  Szegö  K.  Fulle  M. 《Earth, Moon, and Planets》2002,90(1-4):227-238

We briefly describe an advanced 3D gas dynamical model developed for the simulation of theenvironment of active cometary nuclei. The model canhandle realistic nucleus shapes and alternative physical models for the gas and dust production mechanism.The inner gas coma structure is computed by solving self-consistently(a) near to the surface the Boltzman Equation(b) outside of it, Euler or Navier-Stokes equations.The dust distribution is computed from multifluid ``zero-temperature' Euler equations,extrapolated with the help of a Keplerian fountain model.The evolution of the coma during the nucleus orbital and spin motion,is computed as a succession of quasi-steady solutions. Earlier versions of the model using simple,``paedagogic' nuclei have demonstrated that the surface orographyand the surface inhomogeneity contribute similarly to structuring the near-nucleusgas and dust coma,casting a shadow on the automatic attribution of such structures to ``active areas'.The model was recently applied to comet P/Halley, for whichthe nucleus shape is available. In the companion paper of this volume,we show that most near-nucleus dust structuresobserved during the 1986 Halley flybys are reproduced, assuming that the nucleus is strictly homogeneous. Here, we investigate the effect of shape perturbations and homogeneityperturbations. We show that the near nucleus gas coma structure is robust vis-a-vissuch effects. In particular, a random distribution of active and inactive areaswould not affect considerably this structure, suggesting that such areas,even if present, could not be easily identified on images of the coma.  相似文献   

Dynamical response to supernova-induced gas removal in two-component spherical galaxies     

Masahiro Nagashima &#;  Yuzuru Yoshii 《Monthly notices of the Royal Astronomical Society》2003,340(2):509-518

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The growth and structure of dark matter haloes     

D. H. Zhao  H. J. Mo  Y. P. Jing  G. Börner 《Monthly notices of the Royal Astronomical Society》2003,339(1):12-24

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Observational constraint on the fourth derivative of the inflaton potential     

Chiara Caprini  Steen H. Hansen  Martin Kunz 《Monthly notices of the Royal Astronomical Society》2003,339(1):212-214

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Simulations of normal spiral galaxies     

Roelof Bottema 《Monthly notices of the Royal Astronomical Society》2003,344(2):358-384

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On determining the cluster abundance normalization     

Elena Pierpaoli  Stefano Borgani  Douglas Scott  Martin White 《Monthly notices of the Royal Astronomical Society》2003,342(1):163-175

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Application of the global modal approach to the spiral galaxies     

Natalia Orlova  Vladimir Korchagin  Nobuhiro Kikuchi  Shoken. M. Miyama  Aleksei Moiseev 《Astrophysics and Space Science》2003,284(2):739-742

We have tested the applicability of the global modal approach in the density wave theory of spiral structure for a sample of spiral galaxies with measured axisymmetric background properties. We report here the results of the simulations for four galaxies: NGC 488, NGC 628, NGC 1566, and NGC 3938. Using the observed radial distributions for the stellar velocity dispersions and the rotation velocities we have constructed the equilibrium models for the galactic disks in each galaxy and implemented two kinds of stability analyses - the linear global analysis and 2D-nonlinear simulations. In general, the global modal approach is able to reproduce the observed properties of the spiral arms in the galactic disks. The growth of spirals in the galactic disks can be physically understood in terms of amplification by over-reflection at the corotation resonance. Our results support the global modal approach as a theoretical explanation of spiral structure in galaxies. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

Microsatellite Variation in the Oyster Crassostreaplicatula Along the Coast of China     

YU Hong  LI Qi YU Ruihai 《中国海洋大学学报(英文版)》2008,7(4)

Genetic diversity and differentiation of the oyster Crassostreaplicatula populations from China's coast were studied basedon seven microsatellite loci.All loci showed high polymorphism for all five C.plicatula populations,with an average number of alleleper locus of 19.3-27.9 and an average expected heterozygosity of 0.889-0.952.Significant departures from Hardy-Weinberg equilib-rium and deficits of heterozygotes were observed over most populations at each locus,which were fully explained by null alleles.Microsatellite analysis revealed significant subdivision in the C.plicatula populations.According to the neighbor-joining tree con-structed on the basis of the D,A distance,the five populations fell into three regional groups,showing a relatively homogeneous geneticstructure in geographically close populations.Assignation tests correctly assigned high percentages of individuals to their originalpopulations and groups,and also confirmed the existence of genetic differentiation among C.plicatula populations.The results ob-tained in this study will facilitate the formulation of appropriate fisheries management programs,stock identification and conservationof biodiversity for the species.  相似文献   

FLASH redshift survey – I. Observations and catalogue     

Raven Kaldare  Matthew Colless  Somak Raychaudhury  B. A. Peterson 《Monthly notices of the Royal Astronomical Society》2003,339(3):652-662

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